Yosemite at 120: The World's Oldest National Parks

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Before the United States of America had been in existence for 100
years, it had a national park.

In 1872, telephones and radios had not been invented, yet
Yellowstone National Park — the first of its kind in the world
—was carved out of Wyoming, Montana and Idaho to preserve and
protect the outdoors.

Along with Yosemite National Park, which turns
120 years old today (Oct. 1), these two iconic American
spaces inspired an act of Congress that gave birth to the
National Park Service, which hosted nearly 63 million visitors
across all of the nation's parks last year. These earliest parks
were set aside during a daring era of exploration, and while they
are well charted today, not all of their mysterious features have
been explained. [ In
Images: Yellowstone and Yosemite ]

Great Reconnaissance

The period just before and during the Civil War was known as the
Great Reconnaissance in Western exploration. Any scientist with a
passion for discovery had the West as their outdoor laboratory,
ripe for outback expeditions to collect exotic specimens and map
and name amazing geological oddities. Explorers floated the
Colorado River, discovered pterodactyl fossils, and began to poke
around in the mysterious Yellowstone country.

One such explorer with a conservation bent was geologist
Ferdinand Vandeveer Hayden. After an expedition to Yellowstone
was cut short in northwestern Wyoming in 1860 — heavy snow
blocked their path across Two Ocean Plateau near the Continental
Divide — Hayden set out again in 1871, this time boosted by
$40,000 from Uncle Sam.

Hayden and his expedition team, which included a military escort,
packed their wagons and struck out from Ogden, Utah, to the
Yellowstone region, a trip that would take almost two months and
required improvisation. At one point, the explorers even built
their own boat out of an oak tree near Yellowstone Lake. Later in
the trip, an earthquake struck.

Hayden made the most of his expedition, known as the Hayden
Geological Survey of 1871. In his second letter from the area,
Hayden detailed his progress in the Yellowstone wilderness:

". . . made a pretty careful examination of the Geyser region,
Map of the whole region, Charts of the Springs and Geysers, with
temperatures of each. Sketches, Photographs etc. I have made
quite thorough soundings of the Lake, explored the north and west
sides and will now move to the south and east sides. We are
making a good topographical and geological map of the entire
district."

Once Hayden returned from his mission, he successfully prodded
Congress to set aside Yellowstone as a protected park.

Modern mysteries

Today's Yellowstone and Yosemite National Parks are living
laboratories where scientists study the parks' unique geology.

Yellowstone sits in the crater formed by a
supervolcano explosion 640,000 years ago. Today, scientists
are working to understand what drives the regions' volcanic
activity. The crater, called a caldera, has moved upward almost 3
inches (7.6 centimeters) each year between 2004 and 2008. Since
2009, the uplift has significantly slowed, but the movement of
the caldera's floor is considered to be unpredictable. New
research suggests that a
plume of molten rock rising from deep underground may be the
cause.

Also at Yellowstone, geoscientists recently discovered spires
beneath Yellowstone Lake that are very similar to those seen
above ground in other parts of the park. Scientists continue to
explore how these spires formed — the leading idea is that hot
water in a glacially dammed lake molded the rock projections.